Conventional perpendicular magnetic recording (PMR) heads may be unshielded or shielded. Although easier to fabricate and having higher write fields, unshielded heads have a low gradient field. Such a low gradient field results in less sharp transitions and lower signal to noise ratios, which are undesirable. Consequently, shielding is typically provided in conventional PMR heads.
FIG. 1 depicts a portion of a conventional PMR transducer 10, as viewed from the air-bearing surface (ABS). The conventional PMR transducer 10 is a shielded transducer. The conventional PMR transducer 10 is typically part of a merged head including the PMR transducer 10 and a read transducer (not shown) and typically resides on a slider (not shown). For clarity, the conventional PMR transducer 10 is not drawn to scale.
The conventional PMR transducer 10 includes a conventional first pole 12, alumina insulating layer 14, alumina underlayer 16 that may be considered part of the alumina insulating layer 14, a conventional PMR pole 18 that typically includes a seed layer (not shown), insulating layer 20, shield gap 26, and top shield 28. Note that in certain other embodiments, the top shield 28 may also act as pole during writing using the conventional PMR transducer 10. The conventional PMR pole 18 is surrounded by insulating layer 20. Similarly, the top shield 28 is surrounded by another insulating layer (not shown). The conventional PMR pole 18 has sidewalls 22 and 24. In conventional applications, the height of the conventional PMR pole 18 is typically less than approximately three-tenths micrometer. The conventional PMR pole 18 also has a negative angle such that the top of the conventional PMR pole 18 is wider than the bottom of the conventional PMR pole 18. Stated differently, the angle θ of the sidewalls is less than ninety degrees in the conventional PMR pole 18 of FIG. 1. A pole having this height and shape is desirable for use in PMR applications.
FIG. 2 is a flow chart depicting a conventional method 50 for fabricating the conventional PMR transducer 10. The conventional method 50 is a damascene process. For simplicity, some steps are omitted. For clarity, the conventional method 50 is described in the context of the conventional PMR transducer 10. The conventional method 50 starts during formation of the insulating layer 20, via step 52. Typically, the insulating layer is an alumina layer. The insulating layer 20 is etched to form a trench therein, via step 54. The insulating layer is etched using an alumina reactive ion etch (RIE). The trench formed has sidewalls having a negative angle. Thus, the top of the trench is wider than the bottom of the trench. The conventional PMR pole 18 is provided, via step 56. Step 56 typically includes plating material for the conventional PMR pole 18 and performing a planarization. The shield gap 26 is deposited, via step 58. The top shield 28 is provided, via step 60. Thus, the conventional PMR transducer 10 may be fabricated.
Although the conventional method 50 can provide the conventional PMR transducer 10 using a damascene process, the conventional method 50 has drawbacks. The conventional PMR transducer 10 utilizes only a top shield 28. Use of the top shield 28 improves the gradient field. In addition, the net magnetic field from the conventional PMR transducer 10 is at an angle to the perpendicular direction. However, performance of the conventional PMR transducer 10 may still suffer due to stray side fields. Such stray side fields may cause side erasure of adjacent tracks. In addition, such a wider field profile may give rise to increased magnetic track width. Consequently, the reduced track pitch required for ultrahigh density recording may not be achieved. In addition, the method 50 utilizes an alumina RIE in step 54. Typically, this step requires the utilization of a different, expensive tool to complete. Consequently, fabrication of the conventional PMR transducer 10 is made more complex.
FIG. 3 depicts a portion of a conventional PMR transducer 10′, as viewed from the ABS. For clarity, the conventional PMR transducer 10′ is not drawn to scale. Portions of the conventional PMR transducer 10′ are analogous to the conventional PMR transducer 10. Consequently, such components are labeled similarly. Thus, the conventional PMR transducer 10′ includes a conventional first pole 12′, alumina insulating layer 14′, alumina underlayer 16′ that may be considered part of the alumina insulating layer 14′, a conventional PMR pole 18′ that typically includes a seed layer (not shown), shield gap 26′, and shield 28′. The shield 28′ includes top shield 28A and side shield 28B portions. Similarly, the shield gap 26′ includes top gap 26A and side gap 26B portions.
Like the conventional PMR transducer 10, the conventional PMR transducer 10′ is a shielded transducer. However, the conventional PMR transducer 10′ has a wraparound shield 28 including both a top portion 28A and side shields 28B.
FIG. 4 is a flow chart depicting a conventional method 70 for fabricating the conventional PMR head 10′ having a wraparound shield 28′. For simplicity, some steps are omitted. The conventional method 70 is described in the context of the conventional PMR head 10′. The conventional method 70 starts during formation of the PMR pole 18′. The PMR pole 18′ is defined, via step 72. The shield gap 26′ is deposited, via step 74. Thus, both the top gap 26A and the side gap 26B are deposited in step 74. A photoresist mask (not shown) for the shield 28′ is provided, via step 76. The shield 28′ is plated, via step 78. The photoresist mask used for the shield 28′ is then removed, via step 80. Fabrication of the PMR head 10′ is then completed, via step 82. Thus, the PMR head 10′ may be formed.
Thus, the conventional PMR transducer 10′ includes side shields 28B. In contrast to the conventional PMR transducer 10, the method 70 used in fabricating the conventional PMR transducer 10′ does not use a damascene process. Thus, the conventional PMR transducer 10′ is not formed by forming a trench in an insulator and providing the PMR pole 18′ in the trench. Instead, the shield gap 26′ is deposited around an already-formed conventional PMR pole 18′ in step 74 and the shield plated in step 78.
Although the conventional method 70 may be used to fabricate the conventional PMR head 10′, there are significant drawbacks. In particular, the conventional method 70 for fabricating the conventional PMR transducer may be difficult to extend to the conventional PMR pole 18′ having a top width of less than one hundred nanometers. Consequently, the conventional PMR transducer 10′ formed using the method 70 may not be manufacturable at higher densities.
Accordingly, what is needed is an improved method for fabricating a PMR transducer.